Riffle-box.



A. E. GUSTI-1R.

RiFFLE BOX.

AvPucATxoN FILED JUNE 1, 1915.

Patented 111.1y1,1917.v

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ARTHUR E. CUSTER, OFSALT LAKE CITY, UTAH.

RIFFLEJBOX.

Specification of Letters Patent.

Patented May 1, 1917.

Application led J' une 1, 1915. Serial No. 31,6()8.

T 0 all 'whom t may concern Be it known that I, ARTHUR E. CUSTER, a citizen of the United States, residingl at Salt Lake City, in the county'of Salt Lake and State of Utah,` have invented certain new and useful Improvements in Rilile- Boxes, of which the following is a specification.

My invention relates to the saving or recovery of minerals from gravel or ore and has for its object to provide a rifie box having a detachable or false bottom made in sections, wherein are constructed novel recesses or mercury traps to retain mercury which is given a special movement whereby the valuable minerals are separated from the y gravel or crushed rock, and recovered.

These objects I accomplish with the process which is carried out by theldevice illustrated in the accompanying drawings in which simtherein with portions of said boards cut away showing the amalgamating and separating devices.

Fig. 2 is a side elevation of the same with portions of the suspension means cut away, and the position of the riffle boards shown in dotted lines.

Fig. 3 is a plan view, somewhatenlarged from the other views, of one of the riiie boards. V

Fig. 4; is a transverse vertical section of said board on line .fr a 'of Fig. 3.

Fig. 5 is a vertical longitudinal section of one of the mercury traps. Fig. 6 is asimilar view showing the relative position of the mercury and passing material at one step in the process. Fig. 7 is a similar view showing another step in advance, and Fig. 8 is still another similar view showing another advancestep in the process.

' In separating the valuable minerals, such as gold, platinum, silver and other metal having al specific gravity greater than the gangue with which they are associated1 mercury is frequently used to form an amalgam and otherwise treat such minerals, and many forms of jigs, tables, plates, riiiies, sluices, pans and other devices have been lused to separate the said minerals and gangue.

This invention may be used in placer mining and in'other places where the mineral bearing substance or ore must first be crushed and then the treatment applied, and while I may describe the steps and device as applied to vplacer mining it will be obvious that it is applicable to and it is my practice to use it in concentrating mills, behind crushing rolls, and stamps.

@ne of the greatest diliiculties to overcome in placer mining, and more especially so, where the placer deposit under treatment contains line gold, is that the riflles in use become clogged or packed with what is commonly called black sand; this black sand is usually composed of magnetite, ilmenite, and garnets. This black sand soon fills the riflies and forms a blanket-like covering over the mercury and then only the course gold is caught which, owing to its specific gravity settles through this black'sand, thefine gold, however, owing to its finely divided state and the large amount of waterwhich is used to keep the black sand from settlingtoo dense is washedy over and lost. In a great many instances riilles of, a special design have been constructed and tried, where the water was given a certain whirling motion or movement, so as to keep the black sand from settling, however, it `was found that where this .was accomplished, the fine gold was also lost owing to the violent action and rapid flow of the water necessary to keep the black sands from settling. l

In the treatment or process whereby I propose to use mercury as lthe separating medium and for the medium to` lift the black sands out of the riile in a .gentle manner it will be readily seen that no violent action is required and the fine gold as well as the coarse gold can be readily saved.

In the drawings, in Figs. 1 and 2, I have shown a riflie box A., suitably suspended so that a limited longitudinal motion may be imported to it by the eccentric B. A counv ter spring C is used to give a quick return throw to the box. I have found in practice that as the momentum of the box requires that it be short and more riflespace is rebox A and into which the partially treated material is dumped.

The bottoms of said boxes A and D arev provided with rifHe boards E, transversely disposed therein and contiguously placed to form a continuous false bottom in each of said I'iiiie boxes. Each of said boards E has a plurality of recesses 1l cut therein transverse as to the individual board and longitudinal as to the box A. lThe said recesses 1 are parallel and spaced apart and are also in two parallel rows across the-said rilie box and each recess is staggered in its relation to the longitudinally adjacent one. Between the said recesses 1, the cross rifHes 2 are secured to the upper face of said rifie Vright angles to the bottom.

The steps vof my process and the operation of the device are carried out as follows The riffle boards E, are placed as a false and detachable bottom in the said rilile boxes A and D, the lip 5 of one extending over the joint between any contiguous board. The saidriiile boxes are suspended at an incline from the head toward the tail thus giving direction to the flow as shown by the arrows a. Mercury commonly called quicksilver is supplied in said recesses 1 in an amount suiicient to cover the straight b ottom of said recesses and by reason of the inclination of said boards the greater volume or quantity will normally be held in the said pockets o, as shown at g. The reciprocating motion is then imparted to the said rifHe boxes A and D by the eccentrics B. The said boxes will be moved first in the direction of the arrows a, and then in the reverse direction by the more rapid motion of the spring C. The mineral bearing sand and line gravel with enough water to move it slowlygthrough the rifiie box is then fedA into said box A and allowed to flow therefrom at the lower end into and through the other boxes. given to the boxes, which I wil-l hereafter call, the throw motion, will cause the mercury in the recesses 1 to assume a position similar to that shown in Fig. 6. In changing from its normal positionl as shown in Fig. 5 to that shown in Fig. 6, all material having less specific gravity vthan mercury such as `comminuted iron ore commonly called black sand, gravel, fine sand, slimes and water will be carried on the surface of the Iner- The rapid or spring motionv cury. As the mercury is thus moved, the said sands and lighter materials will change their positions from that shown in Fig. 5 as at 1, to that shown in Fig. 6 as at s and the greater portion will be moved by the water toward the tail end of the boxes. All material having a specific gravity greater than mercury, such as gold and platinum will sink through the mercury and settle at the bottom of said recesses. When the eccentrics B have made a complete rotation or movement and the said boxes A and D are again given the forward or slow movement, the mercury still having a momentum in the other direction will ow up the curved or inclined bottom 1, which flow will be stopped by the overhanging lips 3, and the material in said recesses 1 will assume the position shown in Fig. 7, wherein the mercury will bank up at the head end of said recesses and the material of less speciic gravity will be moved by the ow of the water and action of the moving mercury and a portion bank up against the vertical tail ends in the pockets 0. When the mercury settles or is thrown into its vnormal position as shown in Fig. 8, which occurs just after the second throw motion has started, the lmaterial of less specific gravity will be raised and washed over the tail endvof said recesses and advanced down the riflie boxes. The gold and all heavy minerals will settle in said pockets o and leave the mercury free to be moved as before explained and to act as a carrier for the lighter material, and as a screen for all metals having a greater specific gravity than said mercury. The cross riflles 2 and 4 cause all of the mineral bearing material to pass through the said recesses. l

From the description it will be seen that the rifle is self-cleaning, that is, all minerals and gangue having a less specific gravity than the mercury are displaced by the mercury, and the separation is not dependent upon any violent agitation lor large volume of water liowing rapidly, but is accomplished with the gentle action of the mercury by displacement, dueto the differences in specific gravity, this cleaning action being accomplished by subjecting the mercury to a movement in a novel riille having recesses or traps, wherein the physical properties of mercury are taken advantage of and applied to accomplish this action of separating the gold or vplatinum fromy the materials in which they occur, in the free state. In this process the specific gravity and liquid properties of mercury, and the specific gravity of the metals to berecovered and that of the gangue or material in which they occur, play an important part. The specific gravitynof gold, being 19, platinum 16-19, mercury 13, magnetite 5.

In 'the operation of the riiiie the mercury owing to its specific gravity of 13, is used as a sort of wedge or lifting means to separate the gold, etc., from the material in which it is carried by forcing its way between them, thus getting the gold, etc., under it and wedging or lifting the lighter materials out of the recess, thus retaining the gold, etc., by covering it and at the same time cleaning the recess of the other and lighter minerals or gangue, and not allowing them to pack over the surface of the mercury and thus destroy its action as a collector of gold, etc.

By using the mercury as described and subjected to the motion provided it is readily seen that the gold and other metals having a specific gravity greater than the mercury, would be caught and held under the mercury, and so retained whether they amalgamated with it or not, as I have found the case to be with rusty or coated gold,.the other materials or gangue under treatment, of a lighter specific gravity, are iioated and displaced with the mercury and so raised gently out of the riiile recesses or traps into the current of water used in the treatment or process and so conveyed into the neXt recess and worked over and so on to the next until it passes into the waste or tailings dump, the gold, etc., being caught in the riflie recesses and saved, by being covered with a blanket coating of mercury, or amalgamated if the conditions afforded for amalgamation are perfect, owing t0 the long contact 0btained, or in case of rusty gold or coated gold, which will not readily amalgamate, would ,thus be covered and held in the riflle recess with a covering or bath of mercury.

Another feature of my process, which is accomplished with the use of the device invented by me, is that when the mercury is in its normal position, shown in Fig. 5, the

' valuable particles of mineral will fall into the recesses on the sloping bottom l which is not covered with mercury as indicated at t, and when the boxes are given the throw or quick movement the mercury will cover the said particles t so that they are subjected to the action of the mercury, and if small and in condition for amalgamation will be carried by the forward movement in the mercury as amalgam, while if large will be completely covered and carried or rolled into the pockets o by said movement, and do not have to pass directly through the mercury. It is part of my process to use more mercury than is commonly used in order that it is at all times a free moving liquid instead of a slow moving bunch of amalgam after it has commenced to act on the minerals.

Having thus described my invention I desire to secure by Letters Patent and claim 1. In a device of the class described, the combination of a rilfle box; a plurality of detachable riflie boards transversely placed as a secondary bottom in said boX, and each having rows of longitudinal recesses cut in the face thereof, each of said recesses having a portion of its bottom inclined upwardly toward the front end and the other portion curved upwardly and having its rear end at right angles to the inclined portion of the bottom, to form a right-angled pocket, each of said recesses having an overhanging lip at its head end; and means to impart a longitudinal reciprocatory movement to said boX and boards.

2. In a device of the class described the combination of a riiile box; a plurality of detachable riflle boards each having rows of longitudinally disposed recesses cut in the face thereof, each of said recesses having a portion of its bottom inclined upwardly toward the front end and the other portion curved upwardly, and having its rear end vertically at right angles to the inclined portion of the bottom; and means to impart a slow forward movement and a quick return movement to said boX and riflle boards.

In testimony whereof I have aiiiXed my signature in presence of a witness.

ARTHUR E. CUSTER.

Witness:

SAM RANEY.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

